#计算器可以进行基础运算(加、减、乘、除)被除数不为
first = float(input("请输入第一个数: "))
second =float(input("请输入第二个数: "))
operator = input("请选择运算符: + - * /:")
if operator =='+' :
    print(first + second)
elif operator =='-':
    print(first - second)
elif operator =='*':
    print(first * second)
elif operator =='/':
    if second ==0:
        print("除数不能为0" )
else:
    print(first / second)